But, when we expose it on the table, we perceive a glaring anomaly, which disappears upon reflection. Support is lacking on every side save from below. The dorsal pads, the principal ambulacra, take contact with this one surface; and the animal straightway walks upside down. The Cetonia-grub surprises us by the strangeness of its locomotion merely because we are observing it outside its usual environment. It is thus that the other corpulent, short-legged grubs would travel—the grubs of the Cockchafer, the Oryctes[12] or the Anoxia-beetle—were it possible to unroll them entirely and to straighten out the crook of their mighty paunches.
In June, which is laying-season, the old larvæ that have lived through the winter make their preparations for the transformation. The nymphal caskets are contemporary with the ivory globules from which the new generation will emerge. Although rudely made, the Cetonia-cocoons are not without a certain elegance. They are ovoids almost the size of a Pigeon’s egg. Those of the Funeral-pall Cetonia, the smallest of the species inhabiting my heap of leaf-mould, [[25]]are very much smaller, hardly larger than a cherry.
All, however, have the same shape and the same appearance, so much so that, with the exception of the small cocoons of the Funeral-pall Cetonia, I cannot distinguish one from the other. Here the work tells me nothing of the worker; I must wait until the adults come out to name my discoveries correctly. However, as a general rule, subject to many exceptions, the cocoons of the Golden Cetonia have an outside facing of the insect’s droppings, set close together without any definite arrangement. Those of the Metallic Cetonia and the Dark-brown Cetonia are covered with remnants of decayed leaves.
We must regard these differences as resulting merely from the materials that surround the grub at the moment when it is building its cocoon and not from a special method of construction. It seems to me that the Golden Cetonia likes building in the midst of its old dejecta, now hard granules, while the other two prefer cleaner spots. Hence, no doubt, the diversity of the outer layer.
In the case of the three larger Cetoniæ, [[26]]the cocoons are free, that is to say, they do not adhere to a fixed base; they are constructed without a special foundation. The Funeral-pall Cetonia has other methods. If it finds in the leaf-mould a little stone, no larger than a finger-nail, it will by preference build its hut on this; but, if there is no little stone, it can quite well dispense with it and build as the others do, without any firm support.
The inside of the cocoon is smooth as stucco, as is required by the delicate skin first of the grub, then of the nymph. The wall is tough, resisting the pressure of the finger. It consists of a brown, homogeneous material, of a nature which at first is difficult to determine. It must have been a smooth paste which the grub worked in its own fashion, even as the potter works his clay.
Does the ceramic art of the Cetonia likewise employ some sort of fuller’s earth? So we should judge from the books, which agree in regarding the cocoons of the Cockchafer, the Oryctes, the Cetonia and other Beetles as earthy structures. The books, which are generally compilations and not collections of facts directly observed, do not [[27]]inspire me with much confidence. In this instance my doubts are increased, for the Cetonia-larva could not find the necessary clay within a short radius, in the midst of the decayed leaves around it.
I myself, digging this way and that in the heap, should be greatly put to it to collect enough plastic material to fill a thimble. What of the grub, which no longer stirs from its place when the time has come to shut itself up in a cocoon? It can gather only immediately around it. And what does it find? Solely remains of leaves, humus, a bad mortar that does not set. The conclusion is inevitable: the grub must have other resources.
To divulge these resources will perhaps expose me to the foolish accusation of unblushing realism. Certain ideas shock us though they are quite straightforward and consistent with the sacred simplicity of things. Nature has not our scruples: she makes direct for her goal, heedless of our approval and our dislike. Let us silence a delicacy which seems out of place: we must ourselves become animals to a certain small extent, if we wish to understand the beautiful economy of animal industry. Let us [[28]]gloss over things as best we can, but let us not shrink from the truth.
The Cetonia-larva is about to build itself a strong-box in which the transformation, the most delicate of tasks, will be accomplished; it is about to erect itself an enclosing wall, I might almost say, to spin itself a cocoon. The caterpillar, to weave its cocoon withal, has silk-tubes and a spinneret. The Cetonia-larva, which cannot make use of outside things, has nothing at all, it would seem. But this is a mistake. Its poverty is only apparent. Like the caterpillar, it has secret reserves of building-materials; it has even a spinneret, but at the other end of its body. Its store of cement is its intestine.